Ratios of the unknown amounts in a recipe

I dont understand this at all, i didnt even know which category to put this in!
I'm not asking for the answer, i just want to know how to do it, i don't even know where to start!

Jane is making a milkshake. The recipe is 160ml milk 140ml cream and 50ml syrup. The cream is poured into a 350ml jug, then she adds the milk but gets the measurement wrong. She only notices when she goes to pour in the syrup & the jug is full before she pours in the whole 50ml. She calculates the amount she needs to pour out & mixes it well before doing so. She replaces it with a mix of syrup and cream & it ends up the exact same as the intended recipe. What is the ratio that she used to make the syrup & cream replacement? If she emptied 70ml down the basement how much of each ingredient did she get rid of?